Schools are squandering hundreds of millions of pounds a year in unnecessary energy bills, new research has found.

Schools comprise just over half of all public buildings in England and Wales, but only 29 of the 11,993 earned the top “A” rating for energy efficiency last year. The Display Energy Certificate system requires all public buildings to undergo an annual energy efficiency audit, grading them from G — the worst — to A.

Lessen, the energy efficiency group that conducted the survey, says 1,703 schools were given the lowest ranking. The data will provide an impetus to councils struggling with public funding cuts to increase efforts to cut energy consumption.

Alexandra Notay at Lessen said the aim was not to “name and shame” the worst…